Lubricant cooling system



.a et "v4 1 f ,p 2,698,773 I "i 'LUBRICANI COOLING SYSTEM i -Edward J. Kaczor,'-Cleveland, Ohio, assigvnorntox The Ohio` Crankshaft Company Aiipiiefimmaich 17, 1951, serai No. 216,201'

6 Claims. (Cl. 308-172) lThis invention pertains to the art of lubrication and, more particularly, to a lubricant-cooling arrangement for apparatus having a shaft rotating on a vertical axis.

The invention is particularly adapted to the cooling of the lubricant or oil of the lower thrust bearing of vertical-shafted high-frequency motor generators and will be described with particular reference to such equipment, although it will be appreciated that it has broader applications.

In such equipment, the high speed of rotation and the heavy weight of the rotor require a continuous supply of lubricant for the bearings generally of an extremely high viscosity. A considerable amount of heat is generated in the bearing supporting the rotor and the oil flowing through the bearing is utilized not only for lubrication but as a medium for conducting the heat away from the bearing. Heretofore, it has been conventional to draw oil from a sump, ow it through the bearing and discharge it back into the sump. A cooler was submerged in the sump through which a refrigerant, such as water, was continuously circulated to cool the oil.

I have found that, particularly when high-viscosity oils are employed for the lubrication of the bearing, the oil tends to congeal and form an insulating blanket on the surfaces of the cooler, radically lowering the efficiency of the cooler. In some instances, it has been impossible to obtainthe required amount of cooling because of the insulating effect of the congealed oil on the cooling surfaces.

The present invention contemplates a new and improved arrangement of an oil cooler in equipment of the type referred to which overcomes all of the above 'difficulties'- and enables a maximum efficiency of cooling with a mini-- mum-size cooler. i

In accordance with the present invention, slinger means rotating with the shaft are provided above the sump levell which sling lthe oildischarged from the bearing radially outwardly at high velocity and the oil cooler, instead of being submerged below the levelof the oil in the sump, is placed atleast in part above the level of this oil Aand in the direct discharge path of the oil from the slinger means. The slinger means may be inherent in the bearing or may be a separate member fastened to the shaft and rotating therewith. With such anv arrangement, I have found that the velocity of the oilv leavingv the slinger means, is suflicientto break off any oil which may have congealed on the cooler means simply by the force of the impact of the oil on the cooling surfaces. While any type of cooling means may be employed, I have found that a toroidal coil of copper tubing through which water or other refrigerant may be continuously circulated provides a very satisfactory cooling means. A toroidal coil may be positioned coaxial with the axis of rotation whereby all of the oil thrown radially outwardly by the slinger means may impinge on this cooling means and, having been cooled, ow back into the sump.

The principal object of the invention is the provision of a new and improved arrangement of an oil cooler which is simple in construction, economical to manufacture, gives a maximum of cooling with a minimum of cooling surface and which is not troubled with the difficulty of congealed oil serving as an insulating layer on the cooling surfaces and preventing an eilicient transfer of heat from the oil to the cooling means.

Another object of the invention is the provision of new and improved means for cooling the lubricating oil for a bearing supporting a shaft rotating on a vertical axis, which means includes slinger means rotating with the l 2,698,773 Patented Jan. 4, 1955 icc shaft located .above the level of the oil in the oil sump for throwing oil radially outwardly at high velocity and cooling means positioned also above the level of the oil in the oil sump arid directly in the discharge path from the slinger means.

Other and more specific objects willappear upon a reading and understanding of the preferred embodiment of the invention described in this specification.

The invention will be specifically set forth and defined in the claims appended hereto.

The invention may take physical form in a number of different arrangements and combinations of parts and a preferred embodiment of one of such arrangements will be described in detail in this specification and illustrated inhtheaccompanying drawing which is a part hereof; and w erein,

Figure 1 is a fragmentary side sectional view of the.

lower end of a high-frequency motor-generator unit showing a lubricant cooling arrangement embodying the present invention and Figure 2 is a top sectional view of Figure l taken approximately on the line 2-2 thereof.

Referring now to the drawings which are only for the purposes of illustrating the invention and not for the purposes of limiting it, Figure 1 shows a vertically extending shaft 10 journalled for rotation on a base 11 by a pair of bearings 12 and 13. The bearing 12 is for the purpose of supportingl the vertical weight of the shaft while the bearing 13 s for the purpose of supporting the shaft against radial movements and loads.

The base 11 may be of any convenient construction but is generally and preferably a casting machined to the required dimensions and includes, generally, a central cylindrical well or bore 14 coaxial with the axis of rotation of the shaft 10; an upstanding cylindrical flange 15 spaced a considerable distance from the axis of rotation to form an oil sump or reservoir 16 within the base itself and a flat surface 17 intermediate the well 14 and the ange 15 on which the lower side of the outer race of the bearing 12 rests and is confined against radial movement by an upstanding cylindrical shoulder 18. The inner race of the bearing 12 fits snugly around a portion 20 of reduced diameter on the shaft 10 and has, bearing on its upper surface, a flat, washer-like member 21, on the upper surface of which, in turn, the lower side of the inner race of the bearing 13 rests. The shaft 10 is reduced in diameter, as at 23, to fit snugly inside of the inner race of the bearing 13 and has a shoulder 24 which bears on the upper surface of this inner race. The outer race of the upper bearings 13 fits into the opening of a ring-like member 26 which, in turn, fits into the upstanding cylin- -drical flange 15, thus transmitting radial forces of the shaft 10 to the base 11. The ring member 26 has an upstanding portion 27 which extends radially inwardly toward the outer surface of the shaft 10. This portion 27, as shown, is spaced above the upper surface of the upper bearing 13 and forms an oil seal to prevent lubricating oil from passing into the interior of the motor. rinth seal couldbe employed if desired.

The lower end of the shaft 10 has a cylindrical sleeve 30 mounted coaxially thereon, including an upper portion 31 of an external diameter approximating the external diameter of the lower end of the shaft 10 and a lower portion 32 of a lesser diameter which extends into the well 14 of the base 11. As shown, the lower end of the portion 32 is spaced from the bottom of the well 14. The lower portion 32 has helical teeth formed on the outer surface thereof, the outer diameter of which is approximately the diameter of the well 14. These teeth function as an oil pump when the shaft rotates.

The base 11 is also provided with a plurality of generally horizontal radially-extending openings 37 which communicate the lower portion of the oil sump 16 with the upper portion of the well 14. Openings 38 located just radially inwardly on the lower race of the bearing 12 communicates the passages 37 with the inner edges of the roller members of the bearing 12.

As shown, the shaft 10 and the sleeve 30 has aligned axial passages 45 and 46 respectively extending through the bottom of the portion 32 to a point in the shaft above the upper surface of the upper bearing 13. The passage 45 at the upper end communicates radially outwardly of A labythe shaft '10 through a plurality of radial openings 47 which,as-shown,lare located above theupper-Ybearings-l.-

Before commencing operation; that is, in the static condition, the lubricating oil 40 is at a level as shown by the lirici-41. When the shaft;'10.commences'rvogrotate,,the`r 5 helical `teeth: on theoutensurfaceaof theportion;l 3:2,v pump the oilv 40 through the'passages 37: andgdownwardlyf, and` around the bottom .side of the'fportion-,SZ famgthenceff vertically upwardly through the passages 45pand;Mintonl and through .thepassages47 lwhererthe-oilzspills .Onto :the 10 upper .bearing ,13, lubricat'es `it and theni owswback vinto 1, the sump 16.` A

In additionptoz this oil: flow, .the rollers of',thellower bearing 12 move rapidly about lthez. aurisffof:lro,tati o n,-y churning -the oil up in then-bearingl and, becausetoftthe 15 high circumferentialzvelocity, sling it radially:ontwarcllfyv from the, kbearing fbetween ythe uppeLand'-, lower fbearing races .at a -high velocity as shown.-bythendottedolines,z of Figures l and 2.

In accordance with the invention, cooling means-are-.-'20 providedv above the oilk level 43 and' in this, discharge,l path S to coolthe-oilUas it isdischarged from the-.loweri bearing: 12 and to employ ithefirnpact f ofthe; discll-ar-gex. of thexoil on the cooling meansto lcontinually breakgaway@ anyo.l':which tends to congealu-on.' thecooling,.surfaces25 so .thatthe maximum cooling etect canrfbe obtained with a minimum area of coolingsurface.-`v Thefcoolingrnea-ns in the embodiment Vshowni comprises al toroidal; coiltof4 copper ftubing. 51 havingends152,-.53whichap2ass outwardly :through the circulary tlange, iandsrycommunicateg; 30 with afsource 4of faf :cooling mediurrn suchl:aswwater1 ,not shown. The 'coilv 51, as shown; completely surroundsff the lower bearing 12 sothat `all oiladischargedfrom` thefbearing pwill.in1pinge thereonfto be -cooled therebys.

Obviously,` other forms of coolingsmeanscould-beaerw-V ployed such as helical coils of'copper tubingnnedtuhes or, ifdesired, the circular ange may be hollow and Scooling waterl may be circulatedtherethrough.` In this evene.; however, it would be preferred that the inner circumfer-` ential surface'of the ange 15 ;be tinned or the like.V 40

The embodiment shown inthe drawing land-:describedabove has proven to be-extrernelyA practicable in-actual., operation. When the coil was submerged belowl the level-- of the cooling oil, as heretofore done,; it `was 1rnposs1bleto obtain the desired and necessary degree of cooling of theoil.' The oil appeared toV congeal on'thefsurfacesof the coil and acted as an insulatingblanket,preventing the outer hot oil frorncoming into thermal contact with.'` the'cooling .surfaces of the coil itself. Howevenwhen the Videntical coil was raised to a -point above-the Vlevel;5 of the cooling oil in the sump andi in lthe discharge 1path 50, an immediate and very marked increaseintthecooling;` rate .occurredsuch that expensive redesign `ofthe/.entirel lower end of the equipment was no' longerconsidered-.-l necessary.: t 55 Obviously, other-arrangements andcombination-flo parts differing radically from those described 1iri the above-1. specification andillustrated inthe drawing-willyoccup to .others upon a reading and understanding-offthis speci-ycation, and it is my intention to includefall such alteltaw:Y tions 'insofar as they come within the scopeof the-api pended claims which, as heretoforetstatedV specifically set forth anddefine the invention.

Having thus described my invention, l claim:

1.` In --rotatingw equipment, a--fshaft having aavertical oil level and,in thedirect-PatheOftdischarge,from said slinger meansA for 'coolingV said Voil.A

2. In rotating .equiprnentV-,a-; shaft-rhavinga.vertical axis ot'v rotationf ,a-tbea-r'nggmernbera, Qnsupporting said shaft, an 011V sump A, surrounding said bearing member,

" meansior -pumpingrtoil-ithroughesaidgbearinggsaid bearing being ofthe type to-sling the lubricant supplied thereto radially outwardly atahighuvelocity when said shaft is rotating and cooling means including a watercooled coil at least in part above the level in said sump and in fthe. .direct discharge1 .pathof -said bearing Lmember i for :cooling f saitlioillas V.it is..disch'arged .ffromathe bearing member;W l l Y g 3 1, Ingapparatus 'offf'thel type tdescribed; a -vertical shaft supportingrsaid VY'shartl of ,the .type .requiring ,a continuous i` supplyrof fresh lubricant, means .for continuously supply:`

inggfreshlubricant: to said,.bearing.member, meansfforA slinging the lubricant discharged from said bearing radially Suma Y sardegs nging means.

lubfricantrin' said sump rbelow .attleast, in` ,part the, level .of

said bearing member, means-,fonsupplying,alcontinuous.

supply -of 4Alubricantttof.said .bearing`^ member, said bearing,memberebeingconstructedto sling the discharge oil.. therefrom` radially. outwardlyy at ahigh. speed in a plane abovethe rlevel, of oil inl said .lsump and` ycooling .means in` :the` direct dischargefstreamof oil 1from Asaid. bearing. member positioned .above thelevel..oflthe.oil in said sump.;

5.L Thecombination. `of v claim. `4 .wherein said cooling means isV intheform of a toroida'lcol having its principal, pla'netin the planerof .said-,dischargestream and means, for flowing. a coolingn medium through said toroidal coil.

6.,'1`he combination of .clainr 4 wherein. said lubricant is .ofa `type and viscosity/ such. as. `to congealonsaid Vcoolv ingimeans .if-cooledtotthe :approximate temperature of Rt'rences Cited inthele of this. patenti UNITED STATES PATENTS 1,323,769 Jacobson Dec. 2,'1919 1,610,886 Ross Dec.- 14,1926.v 1,987,937 Howarth ..-.Jan.. 15,` 1935 2,568,861 Luenberger Sep t.l25, 1951..`

having -lafvertical'-axisiof rotation; a bearing member .for 

